Clinical thermometers which receive infrared radiation emitted from a human body and display temperature according to the infrared radiation have been used.
For example, PTL 1 discloses an ear thermometer provided with an instruction unit that is arranged in a front surface of a housing in order to instruct start of measurement of body temperature, a rotation unit that, at a position on a rear surface of the housing, which is opposite to a position where the instruction unit is disposed, rotates around a normal line at the position on the rear surface, and a probe that is connected to the rotation unit at a predetermined angle with respect to the normal line and that has an infrared sensor and a thermistor mounted on a tip position thereof.
In these years, an infrared sensor is mounted on a portable apparatus and is used also as a temperature sensor or a human detection sensor.
For example, PTL 2 discloses a portable wireless terminal having an infrared sensor that is incorporated in a vicinity of a liquid crystal display screen thereof and detects temperature of a forehead of a user in a non-contact manner.
Moreover, PTL 3 discloses an optical device in which an optical element is firmly fixed on an optical filter physically and a light reception/emission surface of the optical element is not exposed.
Further, PTL 4 discloses a portable electronic apparatus provided with a human detection sensor having an infrared sensor for detecting infrared radiation generated from a human body and judging means for judging approach of a human body by a first output signal from the infrared sensor.
Infrared sensors provided in portable apparatuses are arranged at positions according to respective purposes thereof. For example, the vicinity of the liquid crystal display screen is selected for the position at which the infrared sensor of PTL 2 is provided as a position to which a forehead of a user may come close. The human detection sensor of PTL 4 is also similarly provided in the vicinity of a liquid crystal display screen.
On the other hand, when an optical fiber is used, limitation on the position of the infrared sensor is eliminated.
For example, PTL 5 discloses a plug-jack type optical and electric shared transmission device. In the optical and electric shared transmission device, when an optical fiber plug is inserted into a common insertion hole provided in a holding body that stores and holds an optical semiconductor element and an electrical connection terminal, optical transmission is performed on the optical semiconductor element in the holding body. On the other hand, when an electrical plug is inserted into the insertion hole, each electrode unit of the electrical connection terminal and the electrical plug are electrically connected, so that electrical signal transmission is performed.